Surface Layer Research Articles

The impact of the destruction of the Kakhovka reservoir dam on the oceanographic conditions in the north-western part of the Black Sea according to the results of modeling

Based on the results of numerical modelling, characteristic features of distribution of transformed and polluted waters of the Dnieper River in the water area of the north-western part of the Black Sea (NWBS) are determined and analyzed. This pollution of the marine environment resulted from the extremely large man-made flood caused by the destruction of the Kakhovka Reservoir dam by the Russian occupation forces in June 2023. Various types of pollutants, which contained in the Kakhovka Reservoir, in the lower Dnieper River and in the bottom sediments, were carried out into the sea by the flood discharge. A significant amount of pollutants was washed into the sea from the flooded areas of the lower Dnieper basin. Special attention is given to changes in oceanographic conditions in the Dnieper-Bug estuary region (DBR) of the Black Sea, which determine the extent of marine pollution. Sea water salinity was used as an indicator of the degree of infiltration of polluted seawater from the estuary into the sea. It was identified that the least transformed river waters with low salinity correspond to high pollution levels. Delft3D-Flow Flexible Mesh hydrodynamic model, developed by Deltares, was used in this study. The simulation was performed for the time period 01 to 30 June 2023. During the first days after the dam break the desalinated and polluted transitional waters, flowing from the Dnieper-Bug estuary, spread over the entire water column down to 15-20 m depth in the DBR area. In this case, the spreading of transitional waters was atypical, as it usually occurs only within the thin near-surface layer of the sea. By mid-June the flow of transitional water with a salinity of 4-6 ‰ covered the entire water column from surface to bottom near the northern coast of the NWBS and over the Odessa Bank. This was facilitated by the supermassive volumes of transformed Dnieper river waters flowing out over a short period of time due to dam break, as well as by the resulting intense gradient currents and mixing caused by spatial gradients in the velocity of the generated currents. The width of the desalinated water plume and its area in the bottom layer were smaller than in the surface layer. The largest vertical salinity gradients were formed to the south of the Odessa Bank, where salinity was 4-6 ‰ in the surface layer and 14-17 ‰ in the bottom. Dilution of the desalinated water plume in the bottom water layer was much more intensive than in the surface water. The character of water circulation pattern in the northern part of the NWBS in the first days after the inflow of transient waters from the Dnieper-Bug estuary was determined by the runoff gradient currents, which later were replaced by wind-driven currents in the Odessa area and over the Odessa Bank, and by the meandering flow of gradient density currents further south. The findings of this study contribute to a better understanding of the impact of the inflow of transformed river waters from the Dnieper-Bug estuary on the variability of oceanographic characteristics and the ecological state of marine waters in the Dnieper-Bug region of the northwestern Black Sea.

A scanning electron microscope evaluation of surface roughness of different clear aligners – A comparative in-Vitro study

Clear aligner are thermoplastic polyurethane materials which produces small increments of tooth movements by each aligner tray. Clinical effectiveness of the treatment largely depend on the mechanical properties of the material. The use of scanning electron microscopy (SEM) in invitro environment allows to evaluate the surface morphology of the aligners The aim of the study is to compare the surface roughness of different types of clear aligners after thermoforming and after invitro aging. A sample of 15 aligners from Group A (DURAN), Group B (ERKODUR), Group C (MONOFLEX) were taken for this study. After screening the subjects were scanned by intraoral scanner and STL file were imported to Maestero 3D software. Then resin models were printed and aligners were fabricated in the models by thermoforming machine. The first set of aligners were scanned by Scanning Electron Microscope and another set of aligners were placed in chewing simulator for simulating intraoral environment. Then the second set of aligners were sent for SEM evaluation. Mean comparison of surface roughness and root mean square surface roughness was compared by paired t test and comparison among the groups was done by one way ANOVA test. The surface roughness of both aligners increased after thermoforming. This could be due to thermoforming process which could be due to temperature variation. After the ageing of the aligners in the invitro environment, there is homogenous and smooth layer of the aligner surfaces which could be due to adhesion of biofilm and polishing effect by chewing strokes.

Interfacial deterioration in highly fluorinated cation-disordered rock-salt cathode: Carbonate-based electrolyte vs. ether-based electrolyte

Cation-disordered rock-salts (DRX) emerge as an intriguing class of high-capacity cathode materials, garnering significant attention in the development of advanced energy-storage systems. Fluorination strategies have been raised to regulate redox and structure for better DRX electrochemical performance. However, research on the interfacial processes during fluorinated DRX cycling remains limited. Here, we evaluate a highly fluorinated DRX, Li2Mn2/3Nb1/3O2F (LMNOF), in different electrolytes to correlate its cycling performance with distinct interfacial evolutions. During cycling in the carbonate-based electrolyte, a thick Mn-containing CEI forms on the LMNOF surface, leading to gradual capacity decay. Intriguingly, the addition of fluoroethylene carbonate (FEC) would bring about surface oxygen loss, Mn-ion dissolution and formation of a fluorinated surface layer by reacting with the LMNOF surface, which critically deteriorate the cycling performance. In comparison, the ether-based electrolyte is compatible with the LMNOF surface, resulting in a more favorable cycling stability. This work sheds light on the interfacial deterioration mechanism of LMNOF cathode in traditional carbonate-based electrolyte, emphasizing the importance of using advanced non-reactive electrolytes to enhance DRX performance.

Chemical Fractions and Magnetic Simulation Based on Machine Learning for Trace Metals in a Sedimentary Column of Lake Taihu

In this study, the chemical fractions (CFs) of trace metal (TMs) and multiple magnetic parameters were analysed in the sedimentary column from the centre of Lake Taihu. The sedimentary column, measuring 53 cm in length, was dated using 210Pb and 137Cs to be 124 years old. Surface layers of the column were found to contain significantly higher concentrations of Cd, Co, Cu, Pb, Sb, Ti, and Zn than the middle and bottom layers. The sedimentary core contained a substantial amount of ferrimagnetic minerals. Most of the TMs were present in the residual state, except for Mn and Pb. The chemical fractions of Cd exhibited the most significant variation with depth. The pollution load index (PLI) indicated moderate TMs pollution levels in the region, whereas the risk assessment code (RAC) classified Mn as being heavily polluted. Multiple linear regression (MLR) and random forest (RF), support vector machine (SVM), and XGBoost (1.7.7.1) machine learning models were used to simulate the RAC and total concentration of TMs, using physical and chemical indicators and magnetic parameters of the sediments as input variables. The MLR model outperformed RF, SVM, and XGBoost in simulating the CFs and total concentrations of most TMs in the sedimentary column, with R2 up to 0.668 and 0.87. The SHapley Additive exPlanations (SHAP) method reveals that χarm/χ is the dominant factor influencing the RAC of As in the XGBoost models. For the RAC of Co and Cu in RF models, C% and N% exhibit greater contributions.

WO2–N co-doped 2D Carbon nanosheets as multifunctional additives for enhancing the electrochemical hydrogen storage performance of Co2B

Co2B, with its high theoretical hydrogen storage capacity, is a potential solid-state hydrogen storage material. However, its poor cycling life limits its practical application. In this work, in order to improve the cycling stability and reversibility of hydrogen absorption and desorption of Co2B, we propose to use WO2–N–C nanosheets as dopants to mix with Co2B, thereby enhancing its practical performance. Two-dimensional tungsten oxide-nitrogen-carbon (WO2–N–C) nanosheets was syntheized via a liquid-phase approach, using a tungstenate-polydopamine precursor followed by thermal treatment. Subsequently, these WO2–N–C nanosheets were compounded with cobalt boride (Co2B) particles through ball milling at various ratios of 1%, 3%, and 5%, which were confirmed by XRD (X-ray diffraction) and SEM (Scanning Electron Microscope) methods. Employing a comprehensive suite of electrochemical analyses, including corrosion potential measurements, polarization curves, step voltammetry, and electrochemical impedance spectroscopy (EIS), we found that the incorporation of WO2–N–C significantly enhances the corrosion resistance and electrochemical activity of Co2B. Furthermore, cyclic life tests revealed that the WO2–N–C-doped Co2B composites exhibit superior discharge capacities and capacity retention rates compared to pristine Co2B. Notably, the 3% WO2–N–C-doped Co2B composite demonstrated the optimal electrochemical performance, achieving a maximum discharge specific capacity of 555 mAh g−1 and maintaining 82% of its initial capacity after 50 cycles. Our findings underscore the dual role of WO2–N–C in not only augmenting the surface electrochemical activity of Co2B but also providing a protective surface layer, thereby enhancing its overall electrochemical performance.

Структурные особенности и трибологические свойства многослойных высокотемпературных плазменных покрытий

Introduction. Multilayer high-temperature coatings obtained using plasma spraying, are studied. The combination of layers of different chemical and phase compositions made it possible to increase wear resistance by 1.5–2.0 times. The purpose of this work is to study the influence of the chemical composition of sprayed coatings on the phase composition, structure, micromechanical and tribological characteristics under conditions of dry sliding friction of surface layers. Materials and methods of research. Coatings A and B consist of sequentially sprayed layers. The first and second layers were sprayed in a reducing atmosphere: the first layer was a heat-resistant self-fluxing powder of two systems: 1 – Fe-Cr-Si-Mn-B-C for coating A and 2 – Fe-Ni-Si-Mn-B-C for coating B; the second layer was a mixture of self-fluxing powder with iron powder in a 1:1 ratio. The third layer was obtained by spraying iron powder in an oxidizing atmosphere to form a metal oxide coating. To create a layer of scale on the surface, coated specimens were subjected to high-temperature annealing at a temperature of 1,000 ℃. The chemical composition and nature of the distribution of elements over the thickness of the coatings were determined by micro-X-ray spectral analysis using a TWSCAN scanning electron microscope with an Oxford energy-dispersive attachment. Microhardness and micromechanical properties were studied using an instrumental microhardness tester of the Fischerscope HM2000 XYm system at a load of 0.980 N. Determination of tribological properties was carried out on a laboratory installation using the “finger-disc” scheme at loads of 30, 75, 100 and 130 N. To measure roughness parameters and obtain 3-D profilometry of surfaces after testing, a non-contact profilometer-profiler Optical profiling system Veeco WYKO NT 1100 was used. Results and discussion. Metallographic studies have shown that the formed multilayer coatings consist of an internal metal layer and an external oxide layer with a total thickness of the entire coating up to 800–850 μm. It is established that the first sprayed layer has the highest level of microhardness, which is due to the high-volume fraction of the strengthening phases contained in it (~ 95 %). It is shown that the coating A has increased wear resistance, which is expressed by minimal weight loss (~ 1.5 times less than that of the coating of the coatimg B), the friction coefficient was f = 0.3 for coating A and f = 0.4 for coating B. The study of wear surfaces has shown that for all selected test loads under sliding friction conditions, the coating of both compositions was preserved, even at a maximum load of 130 N.

Highly Stable Propane Dehydrogenation on a Self-supporting Single-component Zn2SiO4 Catalyst.

Current industrial propane dehydrogenation (PDH) processes predominantly use either toxic Cr-based or expensive Pt-based catalysts, necessitating urgent exploration for alternatives. Herein, we present Zn2SiO4, an easily prepared, cost-effective material, as a highly efficient and stable catalyst for PDH. Uniquely, Zn2SiO4 nanocrystals do not require dispersion on support materials, commonly needed for catalytic active oxide clusters, but function as a self-supporting catalyst instead. During the reaction's induction period, surface Zn species on the Zn2SiO4 crystal reduce to coordinately unsaturated ZnOx single sites, serving as highly active catalytic centers. The Zn2SiO4 catalyst demonstrates a stable performance over 200 hours of PDH operation at 550 °C. We further find that introducing a minuscule amount of CO2 into the propane feed significantly extends the catalyst lifespan to over 2000 hours. This enhancement arises from the special role of CO2 in facilitating the removal of strongly adsorbed H*, preventing the complete reduction of ZnOx. After prolonged reaction, the activity of Zn2SiO4 can be fully restored by etching the surface layer to expose fresh Zn species, available throughout the crystals. The combination of CO2 introduction and catalytic site regeneration strategies is expected to enable a year-long PDH operation using a single batch of Zn2SiO4 catalyst.

Angle-dependent Hall resistivity and longitudinal resistivity of type-II superconductor

We use time-dependent Ginzburg–Landau theory in a three-dimensional model, including thermal noise, to analyze angle-dependent Hall resistivity and longitudinal resistivity of type-II superconductor. The Hall resistivity and longitudinal resistivity are calculated as functions of temperature, magnetic field and the angle θ between the magnetic field and the ab-plane in the vortex-liquid regime. Our theoretical calculations within a self-consistent fluctuation approximation for MgB2 and HgBa2CaCu2O6 materials are in good agreements with the experimental findings for both below and above the critical temperature Tc. We observe that when the field angle decreases, the transition temperature increases and the magnitude of longitudinal resistivity decreases, which is qualitatively comparable to decrease of the perpendicular field component. However, when the magnetic field direction approaches the layer surface, it shows a clear different effect from that of a perpendicular field with the same normal component.

Influence of Zinc Chloride Exposure on Microstructure and Mechanical Behavior of Age-Hardened AZ91 Magnesium Alloy

The AZ91 magnesium alloy was subjected to a complex treatment involving age hardening (supersaturation and artificial aging) and simultaneous surface layer modification. The specimens were supersaturated in contact with a mixture containing varying concentrations of zinc chloride, followed by cooling either in air or water. After supersaturation, the specimens were subjected to artificial aging and then air-cooled. This process resulted in the formation of a surface layer made of zinc-rich phases. The thickness and microstructure of the surface layer were influenced by the process parameters, namely, the zinc chloride content in the mixture and the cooling rate during supersaturation. The treated specimens exhibited favorable tensile strength and greater elongation compared to the as-cast AZ91 alloy, with values comparable to those of the alloy subjected to standard T6 tempering. No cracking of the layer was observed under moderate deformation, though greater deformation resulted in the formation of cracks, primarily in the areas containing the Mg5Al2Zn2 intermetallic phase. The produced layer demonstrated strong metallurgical bonding to the AZ91 substrate.

Phase evolution mechanism of SiC-Al-Si composite under flowing nitrogen at 1600 °C

Resin-bonded SiC-Al-Si composite was prepared and sintered under flowing nitrogen at 1600℃. By adjusting the Al/Si ratio, the controllable synthesis of various non-oxide reinforcing phases was achieved. The phase evolution mechanism was revealed, providing a theoretical foundation for the production and application of novel SiC-based refractory. As flowing nitrogen contained traces of oxygen, both Al and Si in the surface layer of the samples may be oxidized and nitrided. As the Al/Si mass ratio increased, the phase evolution in the surface layer of sintered samples followed this sequence: Si5AlON7→Si3Al3O3N5+AlN-SiC solid solution→AlN-SiC solid solution +Al2O3→Al7O3N5+Al2O3. As Al and Si consumed oxygen and generated non-oxides with multi-morphic sealed pores in the surface layer, the inner layer remained oxygen-free and low-nitrogen, leading to different phase evolution. As the Al/Si mass ratio increased, the phase evolution in the inner layer followed: Si3N4→AlN-SiC solid solution→AlN-SiC solid solution (content increase)→Al4SiC4. The synergistic toughening of various non-oxide resulted in a cold crushing strength of sintered samples exceeding 150 MPa. A reaction model was established.

Rapid detection of ingested acetaminophen on face mask by ambient ionization tandem mass spectrometry

BackgroundA regular face mask is comprised of three layers for resisting moisture, filtration, and absorbing oral fluid, respectively. Since the polymers with different polarities are used to make the layers, a face mask can be used as a sampling tool to retain polar or non-polar chemical and biochemical substances in the exhaled breath. In this study, thermal desorption-electrospray ionization tandem mass spectrometry (TD-ESI/MS/MS), an ambient ionization mass spectrometric technique, was used to detect trace acetaminophen that were exhaled and retained on the surface of different layers in a face mask. ResultsWith probe sampling combined with TD-ESI/MS/MS, the acetaminophen ion signal can be detected at the mouth/nostril region of the face mask after taking the acetaminophen tablet. The experimental results were similar to previous studies for the detection of acetaminophen in blood over time using LC/MS/MS. In addition, the intensities of acetaminophen on different layers of the face mask could reveal the differing distributions of exhaled acetaminophen on each layer. To explore the distribution of acetaminophen on the face mask surface, multiple probes were used to collect samples from different locations of the face mask for analysis. The molecular mapping of acetaminophen on the face mask was rendered by scaling the analyte ion signal intensity based on a temperature color gradient. The cartography showed a higher acetaminophen ion signal distribution on the mouth and nostril regions than in other areas of the face mask. SignificanceOwing to the advantages of a simple, sensitive, and non-invasive sampling approach, drug monitoring could be potentially performed to provide useful information for anti-drug of precision medicine in the future.

Enhanced eDNA monitoring for detection of viable harmful algal bloom species using propidium monoazide

This study investigated the use of propidium monoazide (PMA) to improve the accuracy of environmental DNA (eDNA) monitoring by selectively detecting intracellular DNA (iDNA) from living cells, while excluding extracellular DNA (exDNA) from dead organisms. eDNA samples were collected from various depths off the coast of Tongyeong, South Korea, and analyzed alongside environmental factors, such as temperature, dissolved oxygen, turbidity, and nutrient levels. The results showed that PMA-treated iDNA provided a more accurate estimate of viable harmful algal bloom species (HABs) than total eDNA and DNase-treated iDNA. Strong correlations were found between iDNA (PMA) and environmental factors, particularly nutrient levels and turbidity, suggesting its effectiveness in biological environments. The iDNA (PMA) concentrations were higher in the surface and bottom layers, indicating that these layers were more indicative of living organisms in marine environments. The application of PMA in eDNA monitoring reduces false positives and enhances the detection accuracy of viable HAB species, representing a promising tool for real-time monitoring and management of marine ecosystems.

Performance Characterization of the Field Aged Asphalt Pavement Materials at Mortar Scale: Testing Method Optimization and Rheology Analysis

Performance evaluation at the asphalt mortar scale offers increased sensitivity to aging and is less affected by extraction processes comparated to asphalt mixture. Despite these benefits, there is currently a lack of standardized methods for directly processing mortar samples obtained from field mixtures. This study aims to improve and validate a manufacturing procedure for aged mortar specimens derived from field aging cores, and to evaluate the field damage level of asphalt paving materials at the mortar scale. A novel approach was developed that incorporates warm sieving, compaction, coring, and cutting to manufacture mortar specimens suitable for Dynamic Shear Rheometer (DSR) tests. This study selected mortar specimens with different service ages and conducted rheological tests, including frequency sweep tests and modified Multiple Stress Creep Recovery (MSCR) tests, to assess their rheological performance. And the significance test of all the indcies were conducted to select suitable indcies.The results show the proposed aged mortar manufacture approach can prepare eligible mortar specimens for rheology tests. The rheology test results show that several indices can distinguish different mortar types and service ages, and the indices of surface layer mortar follow a linear relationship with service age. The linear viscoelastic zone (LVE), representative shear modulus (G0), and unrecovered creep compliance at 1.6kPa (Jnr1.6) and 3.2kPa (Jnr3.2) are identified as effective indices for evaluating the behavior of field aged mortar because of their effectiveness, lower variability, and better distinction.

Nanocarbon-Polymer Composites for Next-Generation Breast Implant Materials.

Most breast implants currently used in both reconstructive and cosmetic surgery have a silicone outer shell, which, despite much progress, remains susceptible to mechanical failure, infection, and foreign body response. This study shows that the durability and biocompatibility of breast implant-grade silicone can be enhanced by incorporating carbon nanomaterials of sp2 and sp3 hybridization into the polymer matrix and onto its surface. Plasma treatment of the implant surface can be used to modify platelet adhesion and activation to prevent thrombosis, postoperative infection, and inflammation disorders. The addition of 0.8% graphene flakes resulted in an increase in mechanical strength by 64% and rupture strength by around 77% when compared to pure silicone, whereas when nanodiamond (ND) was used as the additive, the mechanical strength was increased by 19.4% and rupture strength by 37.5%. Composites with a partially embedded surface layer of either graphene or ND showed superior antimicrobial activity and biocompatibility compared to pure silicone. All composite materials were able to sustain the attachment and growth of human dermal fibroblast, with the preferred growth noted on ND-coated surfaces when compared to graphene-coated surfaces. Exposure of these materials to hydrogen plasma for 5, 10, and 20 s led to substantially reduced platelet attachment on the surfaces. Hydrogen-treated pure silicone showed a decrease in platelet attachment for samples treated for 5-20 s, whereas silicone composite showed an almost threefold decrease in platelet attachment for the same plasma treatment times. The absence of platelet activation on the surface of composite materials suggests a significant improvement in hemocompatibility of the material.

Study on freezing separation process through observing microstructure of NaCl solution ice

Freezing desalination is a method to purify saline water. Researchers believe that the salt inclusions distributed inside ice affect the sea ice salinity, but there is not sufficient visualized proof that has been obtained via direct and non-destructive experiments to support this view. Even less study has been carried out on the salt inclusion distribution inside ice below the eutectic temperature. In this paper, a NaCl solution ice sample was prepared with the original mass concentration of 3 wt% using unidirectional heat transfer method. The freezing temperature was −24 ℃, which is lower than −21.2 ℃, the eutectic temperature of NaCl solution. Micro-CT device was used to scan the upper, middle and lower parts of a 3 wt% NaCl solution ice sample and the 5-layer U-Net architecture in DL (deep learning) module of the Dragonfly program was used to segment images to extract the information of interest. The image characteristics of salt inclusions and air bubbles inside the ice were obtained. Very high salt inclusion area proportion was found in the surface layer images of the sample with the maximum area proportion of about 43%. Experiments were also carried out to measure the salinity distribution inside the same solution ice samples. It was found that in the surface and bottom ice layers, the salinity is higher than that of the original solution. In the experiments, for the layers cut from the top and bottom of the 3 wt% NaCl solution ice sample, each of them possesses 10% of the solution ice sample mass, their salinities were 4.28 wt% and 5.41 wt%, respectively. Comparing the measurement results with the micro-CT image processing results, it was found that the variation tendency of the area proportion of salt inclusions is consistent with that of the ice layer salinity. The combination of micro-CT technology with DL image processing method has been proved an effective way to visualize and analyze quantitatively the internal structure of salt solution ice. Then, three NaCl solution samples that have the original mass concentrations of 3 wt%, 6 wt% and 9 wt%, and a pure water sample were frozen under the same conditions. The middle parts of the four ice samples were scanned and the obtained micro-CT images were processed. It can be found that in the middle parts of the three NaCl solution ice samples, the area proportions of salt inclusions increase from top to bottom and are positively correlated with the original salinities of the solution ice. The factors affecting air bubble distribution are more complex than that affecting salt inclusion distribution.

Investigation of tool traverse speed on surface integrity of nano composites processed by friction stir process

This work examines the effects of different tool traverse speeds on the surface integrity of AA7075 reinforced with graphene oxide (GO), silicon carbide (SiC) and graphene nanoplatelets (GNPs) nanoparticles during Friction Stir Processing (FSP). Three different traverse speeds of 20, 25 and 30 mm/min, respectively, were used for FSP operations. The resulting nanocomposites were thoroughly analysed using methods including optical microscopy, tensile testing, fracture morphology analysis, microhardness testing, X-ray Diffraction (XRD), Field Emission Scanning Electron Microscopy-Energy Dispersive X-ray Spectroscopy (FESEM-EDAX) and non-contact surface interferometry. The results show that the creation of a refined microstructure with equiaxed grains was aided by tool traverse speeds between 20 and 25 mm/min. Notably, an Ultimate Tensile Strength (UTS) of 358 MPa, microhardness of 139 HV, refined crystalline size of 47.162 nm and average roughness (Ra) of 1.53 μm were obtained with the AA7075+SiC nanocomposite under tool traverse speed of 25 mm/min. On the contrary, surface layer defects developed at a traversal speed of 30 mm/min. Through the use of mechanical stirring and severe plastic deformation (SPD), this study aids in changing the microstructure of the airplane frames.

S-doped amorphous multi-metal borophosphates for efficient alkaline seawater oxidation with a high corrosion resistance

Direct seawater splitting is a promising strategy for the production of green hydrogen to address water shortage and environmental concerns. However, the primary obstacle in direct seawater splitting is directly related to the high selectivity and durability of oxygen evolution reaction (OER) electrocatalysts. In this study, we developed sulfur-doped multimetal (Ni, Fe, and Co) borophosphates (BPOs) as high-performance OER catalysts for alkalized seawater electrolytes. The incorporated sulfur atoms act as precursors to enhance the corrosion resistance, as they form negatively charged polyanionic surface layers that block the chloride ions. The best catalyst demonstrates an overpotential of 278 mV in alkaline freshwater and 292 mV in alkalized seawater electrolytes when subjected to a current density of 100 mA cm−2. The overpotential disparity between the two media was only 14 mV, suggesting that the material has substantial resistance to chloride corrosion. Furthermore, excellent electrochemical durability was attained for the sulfurized and amorphized multi-metal BPOs, highlighting their high potential as promising catalysts for seawater oxidation.

Evaluation of Shear-Punched Surface Layer Damage in Ultrahigh-Strength TRIP-Aided Steels with Bainitic Ferrite and/or Martensite Matrix Structure

Evaluation of Shear-Punched Surface Layer Damage in Ultrahigh-Strength TRIP-Aided Steels with Bainitic Ferrite and/or Martensite Matrix Structure

Revealing the origin of dendritic deposition regulated solid electrolyte interphase enabled by cation receptor in Zn-ion batteries

Aqueous Zn-metal batteries open up promising prospects for large-scale energy storage due to the advantages of ample components, cost-effectiveness, and safety features. However, the notorious dendritic development and unavoidable hydrogen evolution reaction of Zn have grown to be one of the main barriers inhibiting its further commercialization. Despite substantial studies, the mechanism of nucleation and deposition of Zn2+ ions on zinc layer surfaces remains elusive. Here, inspired by additive, the SnCl2 additive is introduced to initiate the in-situ formation of the ZnS-rich solid electrolyte interphase (SEI) layer on the Zn anode, which creates a protective “shielding effect” that hinders direct contact between water and the zinc surface, suppressing the random growth of Zn dendrites in the whole process. The mechanism of Zn nucleation was revealed by employing high-resolution transmission electron microscopy, consecutive electron diffraction coupled with finite element method (FEM) simulations. Moreover, spontaneously formed 3D architecture consists of micorsized hemispherical Sn particles not only suppresses the Zn dendrite growth by reducing the local current density, but also enables the lateral growth of Zn crystals by increasing the average surface energy. Such an electrolyte enables a long cycle life of over 2000 h in the Zn||Zn cell. Importantly, the assembled Zn||MnVO full cells with SnCl2 electrolyte also delivers substantial capacity (171.1mA h g−1 at 1 A h g−1), presenting a promising application. These discoveries not only deepen the comprehension of fundamental scientific knowledge regarding the microscopic reaction mechanism of the Zn anode but also offer significant insights for optimizing performance.

Influence of Biomass Amendments on Soil CO2 Concentration and Carbon Emission Flux in a Subtropical Karst Ecosystem

Soil in karst areas is rare and precious, and karst carbon sinks play an important role in the global carbon cycle. Therefore, the purpose of karst soil improvement is to improve soil productivity and a carbon sink effect. Biomass amendment experiments in this study included three schemes: filter mud (FM), filter mud + straw + biogas slurry (FSB), and filter mud + straw + cow manure (FSC). The characteristics of soil CO2 production, transport, and the effect on soil respiration carbon emissions in two years were compared and analyzed. The results were as follows: 1. The rate, amount, and depth of CO2 concentration were affected by the combinations with biogas slurry (easy to leach) or cow manure (difficult to decompose). 2. The diurnal variation curves of soil respiration in the FSB- and FSC-improved soils lagged behind those in the control soil for three hours. While the curves of FM-improved soil and the control soil were nearly the same. 3. Soil–air carbon emissions increased by 35.2 tCO2/(km2·a−1) under the FM scheme, decreased by 212.9 tCO2/(km2·a−1) under the FSB scheme, and increased by 279.5 tCO2/(km2·a−1) under the FSC scheme. The results were related to weather CO2 accumulation in the deep or surface layers under different schemes.